Semicarbazide-sensitive amine oxidases in pig dental pulp.

The behaviour of semicarbazide-sensitive amine oxidase (SSAO; E.C. 1.4.3.6) in dental pulp has been studied, with particular reference to the metabolism of 5-hydroxytryptamine (5-HT; serotonin). Kinetic studies using radioactively labelled substrates have confirmed benzylamine, 2-phenylethylamine (PEA) and 5-HT to be substrates for microsomal SSAO from porcine dental pulp. Kinetic substrate-competition studies indicated the presence of two forms of SSAO in dental pulp; one that oxidises benzylamine and PEA but not 5-HT and a second that oxidises 5-HT and PEA but not benzylamine. These two forms also differ in their thermostabilities at 60 and 70 degrees C, although this thermal inactivation is partly reversible.